Patents by Inventor Takashi Kitahira
Takashi Kitahira has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 5302560Abstract: A sintered material for recording/reading (particularly magnetic) head slider is produced by:preparing a powdery mixture which comprises 0.5 to 6.0% by weight of at least one component selected from the component group A consisting of the following elements and compounds thereof, a garnet type compound consisting essentially of erbium oxide and aluminum oxide in amounts of 2 to 12% by weight and 0 (exclusive) to 2 (inclusive) % by weight based on the total composition, respectively, and expressed by the formula Er.sub.3 (Al,Er).sub.2 (AlO.sub.4).sub.3 through (Er, Al).sub.3 Al.sub.2 (AlO.sub.4).sub.3, and the balance being silicon carbide powder:the elements for the component group A being Ti, V, Cr, Mn, Mg, Y, Zr, Nb, Mo, Ba, La, Ce, Gd, Hf, Ta, W, Th, and Cs; andsintering the resultant mass under the application of a high pressure.Further sintering aids of Be, BeO, B and B.sub.4 C may be present. For the garnet type compound, erbium oxide may be used, preferably in combination with alumina.Type: GrantFiled: January 8, 1992Date of Patent: April 12, 1994Assignees: Sumitomo Special Metals Co., Ltd., Nippon Tungsten Co., Ltd.Inventors: Toshiaki Wada, Yoshiaki Katsuyama, Mitsuhiko Furukawa, Takashi Kitahira, Michito Miyahara, Kiyohito Misumi, Masaharu Shiroyama
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Patent number: 4902651Abstract: A material for thin film magnetic head slider particularly suited for high recording, which is obtained by sintering a mixture consisting essentially of:5 to 45% by weight of titanium carbide component;0.2 to 10% by weight of zirconium oxide;0.05 to 2% by weight of oxide of yttrium;0.2 to 25% by weight of aluminum nitride; and the balance of Al.sub.2 O.sub.3 component substituted with 0.5 to 8% by weight being at least one machinability agent selected from the group consisting of oxides of Mg, Ca, B, Ni and Cr and complex oxides thereof.Type: GrantFiled: March 3, 1987Date of Patent: February 20, 1990Assignees: Sumitomo Special Metals, Co., Nippon Tungsten Co., Ltd.Inventors: Toshiaki Wada, Mitsuhiko Furukawa, Masaharu Shiroyama, Mitsuyoshi Nagano, Michito Miyahara, Takashi Kitahira, Shigeki Mohri
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Patent number: 4874725Abstract: A sintered article of silicon carbide containing 2 to 12% by weight of erbium oxide, not more than 2% by weight of aluminum oxide, existing in the form of a composite oxide exhibits remarkable characteristics in resisting to oxidation, thermal shock and corrosion, and shows increased strength at elevated temperatures due to their effect to compaction of resulting structure of the sintered article due to retaining fineness of crystal grains. Those meritorious effects can be enhanced by adding to the aforementioned composition 0.5 to 6.0% by weight of at least one element selected from among titanium, vanadium, chromium, manganese, magnesium, yttrium, zirconium, niobium, molybdenum, barium, lanthanum, cerium, gadolinium, hafnium, tantalum, tungsten, thorium, and cesium or a compound of this element.Type: GrantFiled: December 4, 1987Date of Patent: October 17, 1989Assignee: Nippon Tungsten Co., Ltd.Inventors: Mitsuhiko Furukawa, Takashi Kitahira, Sakae Tanaka, Kiyohito Misumi
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Patent number: 4859638Abstract: A sintered material for recording/reading (particularly magnetic) head slider is produced by:preparing a powdery mixture which comprises 0.5 to 6.0% by weight of at least one component selected from the component group A consisting of the following elements and compounds thereof, a garnet type compound consisting essentially of erbium oxide and aluminum oxide in amounts of 2 to 12% by weight and 0 (exclusive) to 2 (inclusive) % by weight based on the total composition, respectively, and expressed by the formula Er.sub.3 (Al,Er).sub.2 (AlO.sub.4).sub.3 through (Er,Al).sub.3 Al.sub.2 (AlO.sub.4).sub.3, and the balance being silicon carbide powder:the elements for the component group A being Ti, V, Cr, Mn, Mg, Y, Zr, Nb, Mo, Ba, La, Ce, Gd, Hf, Ta, W, Th, and Cs; andsintering the resultant mass under the application of a high pressure.Further sintering aids of Be, BeO, B and B.sub.4 C may be present. For the garnet type compound, erbium oxide may be used, preferably in combination with alumina.Type: GrantFiled: February 16, 1988Date of Patent: August 22, 1989Assignees: Sumitomo Special Metals Co., Ltd., Nippon Tungsten Co., Ltd.Inventors: Toshiaki Wada, Yoshiaki Katsuyama, Mitsuhiko Furukawa, Takashi Kitahira, Michito Miyahara, Kiyohito Misumi, Masaharu Shiroyama
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Patent number: 4582812Abstract: Aluminum oxide substrate material for magnetic heads having improved toughness consisting essentially of: (1) 100 parts by weight, consisting of aluminum oxide and 30 to 50 parts by weight of (TiC+TiO.sub.2), and that provided TiO.sub.2 /(TiC+TiO.sub.2).times.100=5 to 15, (2) 0.5 to 5 parts by weight of addition of free cutting comprising at least one from the group of MgO, NiO, Cr.sub.2 O.sub.3 and ZrO.sub.2, and (3) 0.05 to 2 parts by weight of Y.sub.2 O.sub.3.The method of hot-forming aluminum oxide substrate material for magnetic head having improved sinterability consisting of (a) preparing a green compact by molding a raw material mixture which contains: (1) 100 parts by weight, consisting of aluminum oxide and 30 to 50 percent by weight of (TiC+TiO.sub.2), and that provided TiO.sub.2 /(TiC+TiO.sub.2).times.100=5 to 15, (2) 0.5 to 5 parts by weight of machinability agents comprising at least one from the group of MgO, NiO, Cr.sub.2 O.sub.3 and ZrO.sub.2, and (3) 0.05 to 2 parts by weight of Y.sub.2 O.Type: GrantFiled: August 9, 1984Date of Patent: April 15, 1986Assignees: Nippon Tungsten Co., Ltd., Sumitomo Special Metals Co., Ltd.Inventors: Mitsuhiko Furukawa, Michito Miyahara, Takashi Kitahira, Kiyohito Misumi, Masaharu Shiroyama, Toshiaki Wada
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Patent number: 4438213Abstract: Magnetic head slider material consisting of 5.about.10 percent by weight of silicon, 1.3.about.7.8 percent by weight of tungsten silicide and essentially balanced silicon carbide. And it is method for producing said magnetic head slider material that at the time of which the mixed powder consisting of silicon carbide, carbon and tungsten is sintered, cellulose is also mixed with said mixed powder and sintered together at the same time. And then fibrous micropores are caused to the sintered body by the above-described sintering, after that molten metallic silicon infiltrated into fibrous micropores.Type: GrantFiled: August 31, 1982Date of Patent: March 20, 1984Assignees: Nippon Tungsten Co., Ltd., Sumitomo Special Metals Co., Ltd.Inventors: Mitsuhiki Furukawa, Michito Miyahara, Takashi Kitahira, Kiyohito Misumi, Masaharu Shiroyama, Toshiaki Wada
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Patent number: 4430440Abstract: A material for magnetic head sliders comprises a mixed powder consisting of 40 to 80% by weight of Al.sub.2 O.sub.3 and 20 to 60% by weight of TiO.sub.2, and further contains, per 100 parts by weight of the Al.sub.2 O.sub.3 and TiO.sub.2 mixture, 0.5 to 5 parts by weight of at least one of CaO, MgO and Y.sub.2 O.sub.3, and 0.5 to 10 parts by weight of ZrO.sub.2.Type: GrantFiled: May 28, 1982Date of Patent: February 7, 1984Assignees: Sumitomo Special Metal Co. Ltd., Nippon Tungsten Co., Ltd.Inventors: Toshiaki Wada, Mitsuhiko Furukawa, Michito Miyahara, Masaharu Shiroyama, Kiyohito Misumi, Takashi Kitahira
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Patent number: 4356272Abstract: Sintered bodies having improved sinterability and toughness consist essentially of: (1) 100 parts by weight of titanium carbide, titanium oxide and aluminum oxide, the titanium carbide and titanium oxide accounting for 15 to 60 percent by weight and the aluminum oxide accounting for 85 to 40 percent by weight, the amount of titanium oxide relative to the titanium carbide and titanium oxide being 5 to 15 percent by weight, and (2) 0.039 to 1.575 parts by weight of yttrium. Sintering aids may include at least one of the oxides of magnesium, nickel, molybdenum, chromium, cobalt, iron and manganese.Type: GrantFiled: March 24, 1981Date of Patent: October 26, 1982Assignee: Nippon Tungsten Co., Ltd.Inventors: Yutaka Kanemitsu, Takehiko Hagio, Mitsuhiko Furukawa, Michito Miyahara, Yoshimichi Hara, Takashi Kitahira
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Patent number: 4249914Abstract: The powder mixture consisting of 0.5 to 5 percent by weight of TiN and 99.5 to 95 percent by weight of Al.sub.2 O.sub.3 is first presintered and is subsequently subjected to a hot isostatic pressing so as to produce a sintered product which has the maximum grain size of 2 .mu.m and the hardness of more than H.sub.R A 94.Such sintered product is used as a cutting tool for a high-speed continuous cutting operation.Type: GrantFiled: April 18, 1978Date of Patent: February 10, 1981Assignee: Nippon Tungsten Co., Ltd.Inventors: Kazuki Ogawa, Mitsuhiko Furukawa, Yoshimichi Hara, Takashi Kitahira
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Patent number: 4108652Abstract: A new hot isostatic pressing method produces sintered material having a very fine structure as well as uniform properties by forming a unique capsule such as a titanium capsule of metal over a presintered material for sintering a ceramic cutting tool material is disclosed.Type: GrantFiled: August 17, 1976Date of Patent: August 22, 1978Assignee: Nippon Tungsten Co., Ltd.Inventors: Kazuki Ogawa, Mitsue Koizumi, Mitsuhiko Furukawa, Yoshimichi Hara, Takashi Kitahira